Plunger structure



Patented Feb. 8, 1949 PLUNGER STRUCTURE Henry E. Brandt, North Paul, Minn.

Application April 18, 194:7, Serial No. 742,297

11 claims. (c1. 309-4) y invention relates to a structure oi plung- `er and, while the invention might have various applications, it particularly is designed for use in a plunger movablein a `cylinder such as used in an air pump. `It has been a common practice invention will be fully set forth in the following to have a plunger rod with a plunger usuallyKV of; cupl ishape secured thereto, said rod having a reduced threaded portion on which washers or ,plates were spaced at either side of the end oi said cupA shaped plunger, said reduced portion `loeingthreaded to receive a nut. With this commonly used structure it was necessary toremove the nutand one of said washers or plates if a. new plunger were to be put in place. The costof manufacture of the threaded rod was also considerable. Y

-It is an object of this invention to provide a structure of plunger comprising a plunger rod with one 4or more members permanently attached thereto, as by riveting, together with a plunger and a member engaging the end of said plunger and having resilient parts adapted to spring under one of the members on said rod to hold said plunger in place.

It isa further object of the invention to provide Ya structure of'plunger comp-rising a plunger rod, a member preferably of disk form having a hubsecured to said rod, a plate preferably of circular form overlying said hub and permanently secured to said rod as by riveting, a cup shaped plunger having an apertured end surrounding said plate or washer, together with a second member engaging one side of said end and having a central portion with resilient parts adapted to spring under said plate or washer and hold said plunger in position.

It is more specifically an object of the invention to provide a structure of plunger comprising a plunger rod having a reduced end portion,y a disk-like member having a central hub .apertured to receive said reduced portion, a circular plate overlying said hub and apertured to receive said reduced portion, thev end of said reduced portion being riveted overv said plate so asv to permanently attach said plate and mem ber to said rod, a cup shaped plunger having an apertured end surrounding said plate, a second member having an annular portion of inverted trough shape 'engaging said end anld having a central portion'preferably of cylindrical form of circumferentially spaced, inwardly pressed portions adapted to spring under said plate and hold l saidV plunger in position, together with a Wickv Idescription made in connection with the accompanying drawings in which like reference characters refer to the `same parts l throughout the different views, and in which- Fig. 1 is a central vertical sectionv throughs.

plunger embodying the present invention; y l

Fig. 2 is a top plan view of Fig. 1; Fig. 3 is a bottom plan view of Fig. 1.;

Fig, 4 is a viewY partly' in side elevation and :partly in central vertical section of a holding member used;V 1

Fig. l5 is a bottom plan View of Fig. 4;

Fig. 6 Vis a top plan view Yof a disk member`v I usedyand Fig. 7 is a viewpartly in side ,elevation and partly in central vertical section of the` disk member shown in Fig. 6.

YReferring to fthe drawings, a structure of plunger isshown comprising a plunger rod'IILH Rod Ill'has a reduced portion Illa at one enld and a disk-like member 'I I is provided having an 1 upstanding or offset lcentral hub Ilal apertured to receive reduced portion Illa. at its vtop is provided with a plurality of circumferentially spaced depressed portions IIb forming spaced recesses IIc. While member I'I could be variously formed, in the embodiment of the invention illustrated it is shown as of concavo-convex form with its concaveside atritsA top. A washer or circular plate I2 is provided centrally apertured to receiveportion Illa, the same overlying hub IIa and projecting some distancer beyond thesame. The reduced portion t Illa` is riveted or Weldedover the plate I2 so thatmembers ,I I and IZare securely and permanently attachedtorod I'l. A plunger I3 is prof vided' andwhile'this might be variouslyformed,v in the, embodiment of the 4invention illustrated it is shown-as of cup shaped form, .the same.,

having a flat or disk-like end .portion |3a have. ing a central aperture I3b, said end portion I3a 'surrounding plate I2 and` being adjacent the` plane of plate I2 so that plate I`2 vis partially disposed lin Vthe aperture |319.r A holding member I4 is provided and while this might take various forms, in the embodiment of the invention illus- 1 trated it is shown as having an annular portion Ma of inverted trough shape, the outer side of Y which engages the outer side of end I3a or the iheemboiimeni Qiiheinveniion inspannen Nr OFFICE] are three of the parts I4c. A wick I5 is disposed in portion I4a, said wick thus being of annular form and having one side engaging end I3a. Wick I will be of some porous fabric material such as felt. As shown in Fig, 1, Wick I5 will be substantially rectangular in radial cross section.

When the plunger is assembled members i and I2 will be permanently secured to rod i0 as above described. Plunger I3 will Vbeformed and placed in position substantially as shown in-Fig. 2. Wick portion I5 will be placed in member I4 and portion I4b will now be moved through opening I3b about plate I2 and will be forced down around plate I2, the same compressing or distortingsuiciently to permit portions I4c to resiliently snap or spring under plate I2. Portions I4c will be aligned with the recesses llc. -B ember I4 and wick I5 now engage the end I31a and plunger I 3 is held securely in position. Wick I5 will vbe suitably saturated with some lubricant and this will pass into plunger I3 which will be of leather or some similar material so that plunger I3 isfkept lubricated. Whenit is desired to removeplunger I3 as W-hen -a new one is to beput in place, the portion I4b can be readily Asprung upward by inserting a screw driver or other tool thereunder.

Member I4 can thus-be removed and plunger I- 3 then lifted and removed. With `the described structure itis not necessary to unscrew anut and remove a washer as has heretofore been customary. A nut often becomes corroded and stuck to the threads of the rod so that it is diiiicult toy remove. With -the present structure all that `is necessary is to prymember I4 loose. It is also a Ymuch less diicult and less expensive job 'in a shop to secure members I I and I2 to plunger Il). The washer or plate I2 is provided with a rounded edge at its outer side so Ythat portion I4b will readily move thereover. When plunger I3 and rod I0 are moved on the air compressing stroke, which would be upward, as seen in Fig. l, plunger I3 will expand somewhat at its periphery and will move vdown in engagement with member II so as to be :backed or supported thereby. The air ,thus cannot pass plunger I3. When the plunger moves on the air intake stroke, which would be downwardly, as lseen in Fig. v1, plunger I3 moves away from disk I I, as shown vin Fig. 2, and air can then be drawn past plunger I 3 by moving over disk II and through aperture [3b. as indicated by the arrow line Ain Fig. 1.

From the above descriptionit will be seen that I have provided a simple, eiicientandinexpensive structure of plunger. The structure permits ready removal of the plunger member so that it can be readily removed Yand replaced when desired. The parts are quite simple and can be easily and inexpensively made. The device Yhas been amply demonstrated in ,actual practice, found to be very successful and efficient and is being commercially made.

`Tt will of course be understood that various changes may be made in the form, details, varrangement and proportions of the p arts, without departing from the scope of applicants invention, which generally stated, consists in a device capable of carrying out the objects above set forth, in the parts and combinations of parts disclosed and defined in the appended claims.

`What is claimed is:

1. vA plunger structure having in combination .a plunger rod, a member secured to said rod adjacent the end thereof, a washer overlying said member and spaced therefrom ,at circumferentially spaced `points and secured to said rod,

lio

a cup-shaped plunger having a peripheral ange directed away from said member and having an apertured inner end extending about said Washer adjacent the plane thereof, and a member engaging the outer side of said inner end and having a central portion with resilient parts constructed and arranged to engage under said Washer to hold said plunger in place.

2. A structure of plunger for a cylinder having in combination, a .plunger rod, a disk-like member having a hub portion apertured for and secured to said rod, a plate overlying said hub and projecting outwardly therefrom, a cup-shaped plunger having an apertured end surrounding said plate, ,a second member having portions engaging the side of said end remote from said plate and having a central portion having spaced resilient parts adapted to engage under said plate to hold said plunger in place.

3. The structure set forth in claim 2, said hub having spaced depressed .portions to accommodate said last mentioned parts.

1. A structure of plunger for acylinder having in combination, a plunger rod, `a concave .disklike member having a hub secured to said rod adjacent the end thereof, a plate voverlying said hub and secured to said rod, a cup-shaped plunger having a cylindrical wall vand an aperture disk.- like end extending about said plate, a second member engaging the side of -said end within said wall and having a central portion with spaced resilient parts adapted to be enga-ged Aunder said plate to hold said plunger in position.

-5. A structure of plunger lfor a cylinder having in combination, a plunger rod, a disk-likemember having a central hub secured to said rod adjacent the end thereof, a circular plate overlying said hub secured vto said rod, a cup-shaped plunger having an apertured disk-like end surrounding said plate, a second member having an annular portion of inverted trough shape engaging the side of said disk-like end opposite said first mentioned member, and having Ya cylindrical central portion having inwardly pressed spaced resilient parts adapted to spring under said plate Ytoliold said plunger in position.

6. The structure setforth in claim 5, saidjhub having spaced depressed portions f or accommodating said parts.

'7. A structure of plunger for a cylinder having in combination, a plunger rod, a member having a central hub secured to said rod adjacent the `end thereof, a circular plate overlying said hub, said rod having a Areduced portion extending through said hub and plate and riveted over the top vof said plate, a cup-shaped plunger having an apertured lat end surrounding said plate, a second member havingan annular portion engagingsaid nat end and having a central cylindrical portion having spaced resilient parts adapted .to spring under and be disposed under said vplate to 4hold said `plunger in position.

8. The structure set forth in claim ,7, said annular portion beingof inverted `troughshape and a wick disposed therein in engagement with said plunger.

A9. The structure set forth in claim 7, said 4hub having spaced depressedportions adaptedlto yalign with and accommodate said parts.

10. The structure set forth in claim '1, said .first mentioned member having a disk-like portion about said hub disposed adjacent .said plunger and forming a A backing therefor.

11. A plunger structure .having incomblnation. a plunger rod, a plate-like member secured to said cumferentially spaced resilient parts constructed Number and arranged to engage under said plate to hold 1,531,234 said plunger in place whereby said parts can be 210551104 sprung to release said last mentioned member and 10 2089963 plunger.

HENRY E. BRANDT.

REFERENCES CITED The following references are of record in the nie of this patent:

UNITED STATES PATENTS Name Date Davis Mar. 24, 1925 Hewitt et al Sept. 22, 1936 Johnson Aug.k17, 1937 

